Vaginal immunology and microbiome composition: bacterial vaginosis in a macaque model

Nonhuman primates (NHPs) are important animal models for the study of human health and disease. In particular, the use of NHPs to study the vaginal microbiome and susceptibility to infections (such as HIV and herpesvirus) is exceptionally valuable due to the similarity in anatomy and physiology. An important aspect to this is maintaining a healthy vaginal microbiome which then minimizes colonization by pathogens and resulting inflammation along the mucosa. In women, conditions such as bacterial vaginosis (BV) are frequently treated with antibiotics such as metronidazole or clindamycin. Due to the excessive use of antimicrobials in medicine and agriculture, alternative compounds and therapies are highly desired to treat infections. Approaches that have been developed and used for vaginal infections includes the use of natural antimicrobials such as essential oils, probiotics, and live cultures, which mimic and function like antibiotics but lack development of resistance like classic antibiotics. However, these approaches have been minimally studied in humans and animals. Effectiveness of essential oils are anecdotal at best. Microbiome manipulation on the other hand has been investigated more thoroughly. Novel products are being distributed for medical use and are monotherapies containing Lactobacillus which colonize the vaginal mucosa (Ali et al., 2020; Brichacek et al., 2013; Lagenaur, Sanders-Beer, et al., 2011). Unfortunately, these therapies have limitations due to durability and individual response in women. By evaluating the extent by which the NHP vaginal mucosa can be colonized with exogenously delivered bacteria, this animal model will highlight the NHP for use in translational studies which use essential oils and beneficial microbiome bacteria for vaginal delivery.